The present applicant has already proposed a position sensor for optically sensing a pressed position (see PTL 1, for example). This position sensor includes: an optical waveguide in a sheet form including two cladding layers each in a sheet form, and a plurality of linear cores arranged in a lattice form and serving as an optical path, the cores being held between the two cladding layers; a light-emitting element for propagating light through the cores arranged in the lattice form; and a light-receiving element for receiving the propagated light. When part of the surface of the position sensor itself corresponding to the cores arranged in the lattice form is pressed with a pen tip and the like, some of the cores corresponding to the pressed part are deformed. Thus, the level of light coming from the cores corresponding to the pressed part and detected by the light-receiving element is decreased, so that the pressed position is sensed. Each intersection of the cores arranged in the lattice form is a continuous intersection where cores 12 are continuous, as shown in FIG. 7.
In an optical waveguide having intersecting cores, it has been proposed to reduce intersection losses (light propagation losses at intersections) by providing an intersection in the form of a discontinuous intersection, as shown in FIG. 8 (see PTL 2, for example). Specifically, at the discontinuous intersection of cores 22 including first and second cores 22a and 22b extending in two intersecting directions, the first core (horizontal core as seen in FIG. 8) 22a is separated by the second core (vertical core as seen in FIG. 8) 22b, and a gap G is formed between the separating second core 22b and each of the separated end portions of the separated first core 22a. In the separated first core 22a, the intersection loss is increased because light leakage from the gaps G occurs in the separated first core 22a. In the separating second core 22b, the intersection loss is 0 (zero) because the second core 22b is a straight core 22 having no separated locations and no continuous intersections. Thus, the intersection losses in the cores 22a and 22b extending in the two intersecting directions are reduced in total.